86 lines
2.0 KiB
C++
86 lines
2.0 KiB
C++
/* mbed Microcontroller Library - SPIHalfDuplex
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* Copyright (c) 2010-2011 ARM Limited. All rights reserved.
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*/
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#ifndef MBED_SPIHALFDUPLEX_H
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#define MBED_SPIHALFDUPLEX_H
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#include "platform.h"
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#if DEVICE_SPI
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#include "SPI.h"
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namespace mbed {
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/** A SPI half-duplex master, used for communicating with SPI slave devices
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* over a shared data line.
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*
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* The default format is set to 8-bits for both master and slave, and a
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* clock frequency of 1MHz
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*
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* Most SPI devies will also require Chip Select and Reset signals. These
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* can be controlled using <DigitalOut> pins.
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*
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* Although this is for a shared data line, both MISO and MOSI are defined,
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* and should be tied together externally to the mbed. This class handles
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* the tri-stating of the MOSI pin.
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*
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* Example:
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* @code
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* // Send a byte to a SPI half-duplex slave, and record the response
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*
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* #include "mbed.h"
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*
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* SPIHalfDuplex device(p5, p6, p7) // mosi, miso, sclk
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*
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* int main() {
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* int respone = device.write(0xAA);
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* }
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* @endcode
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*/
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class SPIHalfDuplex : public SPI {
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public:
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/** Create a SPI half-duplex master connected to the specified pins
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*
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* Pin Options:
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* (5, 6, 7) or (11, 12, 13)
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*
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* mosi or miso can be specfied as NC if not used
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*
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* @param mosi SPI Master Out, Slave In pin
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* @param miso SPI Master In, Slave Out pin
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* @param sclk SPI Clock pin
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* @param name (optional) A string to identify the object
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*/
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SPIHalfDuplex(PinName mosi, PinName miso, PinName sclk);
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/** Write to the SPI Slave and return the response
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*
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* @param value Data to be sent to the SPI slave
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*
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* @returns
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* Response from the SPI slave
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*/
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virtual int write(int value);
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/** Set the number of databits expected from the slave, from 4-16
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*
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* @param sbits Number of expected bits in the slave response
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*/
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void slave_format(int sbits);
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protected:
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PinName _mosi;
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PinName _miso;
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int _sbits;
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}; // End of class
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} // End of namespace mbed
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#endif
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#endif
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